Optical Film For Reducing Color Shift And Liquid Crystal Display Having The Same

Abstract

A liquid crystal display for reducing color shift includes a liquid crystal layer, which is disposed between front and rear polarizer layers, and an optical film for reducing color shift, which is disposed between the liquid crystal layer and the front polarizer layer. The optical film includes a background layer and a plurality of lens sections engraved in the background layer, the lens sections being spaced apart from each other. Light emitted from the liquid crystal layer has different colors depending on the viewing angle and the grayscale level owing to birefringence characteristics of the liquid crystal layer. The optical film diffuses a portion of the light incident onto each of the lens sections so that the portion of the light is mixed with another portion of the light passing between adjacent lens sections.

1 . An optical film for reducing color shift in a liquid crystal display in which light emitted from a liquid crystal layer has different colors depending on a viewing angle and a grayscale level owing to birefringence characteristics of the liquid crystal layer, the optical film comprising:
 a background layer; and   a plurality of lens sections formed in the background layer, and spaced apart from each other,   wherein the lens sections and the background layer have a refractive index gradient that a refractive index gradually changes in a direction from the lens sections to the background layer, and   a portion of the light incident onto each of the lens sections is diffused and is mixed with another portion of the light passing between adjacent lens sections.   
     
     
         2 . The optical film of  claim 1 , wherein the refractive index gradient is provided in a width direction of each of the lens sections. 
     
     
         3 . The optical film of  claim 1 , wherein
 each of the lens sections has a  1 L portion adjacent to the background layer,   the background layer has a  1 B portion to an nB portion, the  1 B portion being more adjacent to the  1 L portion than the nB portion, and   a refractive index of the  1 B portion is more similar to a refractive index of the  1 L portion than a refractive index of the nB portion.   
     
     
         4 . The optical film of  claim 3 , wherein the  1 L portion and the  1 B portion to the nB portion are arranged in a width direction of each of the lens sections, thereby the refractive index gradient being one-dimensional in the width direction of each of the lens sections. 
     
     
         5 . The optical film of  claim 3 , wherein the n is a natural number of 2 or greater. 
     
     
         6 . The optical film of  claim 1 , wherein
 the background layer has a  1 B portion adjacent to each of the lens sections,   each of the lens sections has a  1 L portion to an nL portion, the  1 L portion being more adjacent to the  1 B portion than the nL portion, and   a refractive index of the  1 L portion is more similar to a refractive index of the  1 B portion than a refractive index of the nL portion.   
     
     
         7 . The optical film of  claim 6 , wherein the  1 B portion and the  1 L portion to the nL portion are arranged in a width direction of each of the lens sections, thereby the refractive index gradient being one-dimensional in the width direction of each of the lens sections. 
     
     
         8 . The optical film of  claim 6 , wherein the n is a natural number of 2 or greater. 
     
     
         9 . The optical film of  claim 1 , wherein the refractive index gradient is provided one-dimensionally only in the width direction of each of the lens sections. 
     
     
         10 . The optical film of  claim 9 , wherein a refractive index of each of the lens sections is symmetric about a centerline in a depth direction thereof. 
     
     
         11 . The optical film of  claim 1 , wherein the lens sections have a pattern selected from the group consisting of stripes having a polygonal cross-section, waves having a polygonal cross-section, a matrix having a polygonal cross-section, a honeycomb having a polygonal cross-section, dots having a polygonal cross-section, concentric circles having a polygonal cross-section, stripes having a semicircular cross-section, waves having a semicircular cross-section, a matrix having a semicircular cross-section, a honeycomb having a semicircular cross-section, dots having a semicircular cross-section, concentric circles having a semicircular cross-section, stripes having a semi-elliptical cross-section, waves having a semi-elliptical cross-section, a matrix having a semi-elliptical cross-section, a honeycomb having a semi-elliptical cross-section, dots having a semi-elliptical cross-section, concentric circles having a semi-elliptical cross-section, stripes having a semi-oval cross-section, waves having a semi-oval cross-section, a matrix having a semi-oval cross-section, a honeycomb having a semi-oval cross-section, dots having a semi-oval cross-section, and concentric circles having a semi-oval cross-section. 
     
     
         12 . The optical film of  claim 1 , wherein the lens sections are buried in the background layer. 
     
     
         13 . The optical film of  claim 1 , wherein the background layer has adhesivenss in itself. 
     
     
         14 . A liquid crystal display comprising the optical film recited in  claim 1 . 
     
     
         15 . The liquid crystal display of  claim 14 , wherein the lens sections of the optical film for reducing color shift are formed in a rear surface of the background layer that faces a display panel of the liquid crystal display. 
     
     
         16 . The liquid crystal display of  claim 14 , wherein the optical film for reducing color shift is in close contact with a display panel of the liquid crystal display. 
     
     
         17 . The liquid crystal display of  claim 16 , further comprising an adhesive, the optical film for reducing color shift being attached to the display panel via the adhesive. 
     
     
         18 . The liquid crystal display of  claim 16 , wherein the background layer has adhesiveness in itself so as to be directly attached to the display panel.